Crack-Prone Scissors May Burn Patients, Da Vinci Maker Says


May 13, 2013

Intuitive Surgical, the embattled manufacturer of the da Vinci robotic surgical system, warned customers last week that certain versions of its cautery scissors may develop microcracks that could leak electrical energy and inadvertently burn tissue.

The instrument in question, EndoWrist Hot Shears Monopolar Curved Scissors, is used to cut and coagulate tissue in a wide variety of procedures, including hysterectomy, prostatectomy, and gastric bypass. The scissors and other EndoWrist instruments are made exclusively for use with the da Vinci Surgical System, consisting of a console from which a surgeon manipulates instruments attached to robotic arms while viewing the procedure in 3 dimensions. Some 2000 systems are installed at US hospitals.

In an "urgent medical device notification" dated May 8, Intuitive Surgical stated that "certain -09 and -10 versions" of the scissors may develop energy-leaking microcracks near the distal end of the shaft after the instruments are cleaned and sterilized. "These microcracks may not be visible to the user," the company emphasized. It advised customers to take precautions to minimize the risk for inadvertent burns, such as not applying electrical energy when the instrument tip is not in direct contact with tissue and taking note of any anatomy touching the instrument shaft or wrist.

The company told customers that they will be notified when they can obtain replacement scissors "without the potential for microcracks."

In an email to Medscape Medical News, Intuitive Surgical stated that replacement scissors should be available in 2 to 4 weeks, adding that the company has reported the problem with the cautery scissors to the US Food and Drug Administration (FDA).

FDA spokesperson Synim Rivers said the issue is "under review."

When asked why it is not recalling the crack-prone cautery scissors, Intuitive Surgical said "the company considered the risk to patients of removing the product from the field, which included cancelled or postponed surgeries in cancer patients as well as conversion to more invasive open surgical procedures. The company determined that the risks of device removal before a replacement could be offered outweighed the risks of leaving the existing product in the field."

Intuitive Surgical noted that "in over a million surgeries with these instruments, the company has no confirmed evidence of patient injury attributable to this issue." In its medical device notification, the company said that according to its analysis, there has been only a single complaint of an injury linked to an instrument later found to have microcracks. "However, laboratory testing did not detect any energy leakage."

The descriptors "-09" and "-10" for the cautery scissors refer to product versions, not the year in which the instrument was manufactured.

FDA Surveying Surgeons About da Vinci System After Spike in Reports

The FDA has received reports of patients sustaining accidental burns when a physician performing surgery with the da Vinci system used the monopolar curved scissors. Such adverse event reports (AERs) are filed with the agency's Manufacturer and User Facility Experience (MAUDE) database.

"The surgeon noted the instrument was arcing unintentionally, and burned the uterus," stated a report about the scissors, filed in September 2012. "The tip was changed out and it continued to arc. A new instrument was opened and functioned without problems."

The MAUDE database shows that the number of AERs for accidental burns, punctures, and other mishaps — some followed by a patient's death — that were associated with the da Vinci Surgical System and its various instruments increased 34% from 2011 to 2012. During that period, the number of da Vinci procedures in the United States increased 26%, going from 292,000 to 367,000, according to a financial report for the first quarter of 2013 that Intuitive Surgical filed last month with the US Securities and Exchange Commission.

In response to the spike in AERs, the FDA began surveying da Vinci surgeons earlier this year about their experience with the technology. They were asked about user training, common equipment repairs, patient selection, the complications they saw and how they compared with those seen in conventional surgeries, and what procedures are the best and least suited for this form of robot-assisted surgery.

Intuitive Surgical is a defendant in roughly 26 individual product liability lawsuits filed by plaintiffs who claim that an equipment defect or inadequate training for a da Vinci surgeon led to injury or death, according to the company's latest quarterly report. The company also notes that plaintiffs' attorneys "are engaged in growing and well-funded national advertising campaigns soliciting clients who have undergone da Vinci surgery and claim to have suffered an injury."

The volume of this litigation has substantially increased, but the company believes it has "meritorious defenses" in the lawsuits, said Intuitive Surgical.


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